small changes to text

README

@@ -194,10 +194,10 @@ Metalink
 The current implementation supports HTTP(S)/FTP/BitTorrent.  The other
 P2P protocols are ignored.
 
-For checksum checking, MD5, SHA1, SHA256 are supported. If multiple
-hash algorithms are provided, aria2 uses SHA1. If checksum checking is
-failed, aria2 doesn't retry the download and just exits with non-zero
-return code.
+For checksum verification, MD5, SHA1, and SHA256 are supported. If 
+multiple hash algorithms are provided, aria2 uses SHA1. If whole file
+checksum verification fails, aria2 doesn't retry the download and just 
+exits with non-zero return code.
 
 The supported user preferences are version, language, location,
 protocol and os.